Parent Layer: Stormwater and Sanitation

Name: EH Septic Shallow Groundwater

Display Field: Type

Type: Feature Layer

Geometry Type: esriGeometryPolygon

Description: Presence of shallow groundwater is one of the most significant potential constraints to proper performance of onsite wastewater treatment systems (OWTS, aka septic systems) in Santa Cruz County. Effective treatment of wastewater is promoted by unsaturated soil conditions and presence of shallow groundwater can lead to transport of untreated effluent with potential contamination of surface water and groundwater. Proper design of an OWTS requires a determination of the expected depth of groundwater and design of the dispersal to maintain an adequate separation of unsaturated soil between the bottom of the system and groundwater. Where adequate separation cannot be provided, enhanced treatment components may be required to reduce contaminants prior to discharge of effluent to the soil. Requirements for groundwater separation are specified in SCC 7.38.150(B)(9).Depth to shallow groundwater fluctuates significantly in Santa Cruz County based on rainfall amounts and topography. The depth may fluctuate as much as 20 feet in a given location from summer to winter. Because of this wide fluctuation, observation of shallow groundwater depth for the purposes of designing an OWTS can only be done during wet winter conditions, when at least 60% of the mean annual rainfall has occurred and at least 6 inches of rain has fallen in the previous 30 days (SCC 7.38.120(B).Given the limited amount of time in any given year that observations of shallow groundwater can be made, it is important to have good mapped information to indicate where shallow groundwater may occur and at what depth that be expected to occur. This is particularly important when designing repairs of failing OWTS during the summer months and other situations where groundwater depth needs to be estimated. Environmental Health currently has some record of observed or estimated shallow groundwater depth for almost 8000 parcels in the County. In addition, in 1986-88 EH installed some 50 boreholes and 20 shallow monitoring wells to monitor shallow groundwater levels in communities of the San Lorenzo Valley. Monitoring of some shallow wells continues to determine current conditions relative to historical levels.

Service Item Id: 01c25ade6fc2424a93a02f392bdb58ba

Copyright Text: Potential Shallow Groundwater: Countywide locations and soils likely to experience shallow groundwater were mapped on USDA soil maps in 1977 by County Water Quality Chemist Robert Aston as part of the Growth Management Plan Environmental Report (1977), with input from Environmental Health District Specialists. Shallow Groundwater Likely: Depth of likely shallow groundwater in San Lorenzo Valley communities was mapped based on data from 50 boreholes drilled in 1986, winter observations of groundwater in boreholes and monitoring wells, and Environmental Health file records of winter groundwater observations related to applications for onsite wastewater treatment systems. Maps were drawn by Environmental Health staff, John Ricker and Tom Graves, based on recorded groundwater observations and local topography. The indicated range of likely groundwater depth is the depth that is expected to occur approximately 10% of the time. Ninety percent of the time during an average year groundwater depth would be expected to be deeper than indicated. For more information on OWTS performance and shallow groundwater see the Santa Cruz County Local Agency Management Program for Onsite Wastewater Treatment Systems (LAMP: https://www.scceh.org/NewHome/Programs/LandUse/LocalAgencyManagementProgram.aspx) Data on shallow groundwater depth from the Environmental Health files is available in the layer EH Septic Site Extract, and can also be accessed from individual parcel files: https://sccdocs.santacruzcounty.us/ENV/CustomSearch.aspx?SearchName=SepticandWaterWells&repo=EnvironmentalHealth&cr=1

Default Visibility: false

MaxRecordCount: 2000

Supported Query Formats: JSON, geoJSON

Min Scale: 0

Max Scale: 0

Supports Advanced Queries: true

Supports Statistics: true

Has Labels: true

Can Modify Layer: true

Can Scale Symbols: false

Use Standardized Queries: true

Supports Datum Transformation: true

Extent:

XMin: 6042728.052764386
YMin: 1771114.4817110598
XMax: 6241300.069661558
YMax: 1899533.8341238052
Spatial Reference: PROJCS["NAD_1983_StatePlane_California_III_FIPS_0403_Feet",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",6561666.666666666],PARAMETER["False_Northing",1640416.666666667],PARAMETER["Central_Meridian",-120.5],PARAMETER["Standard_Parallel_1",37.06666666666667],PARAMETER["Standard_Parallel_2",38.43333333333333],PARAMETER["Latitude_Of_Origin",36.5],UNIT["Foot_US",0.3048006096012192]],VERTCS["NAVD_1988",VDATUM["North_American_Vertical_Datum_1988"],PARAMETER["Vertical_Shift",0.0],PARAMETER["Direction",1.0],UNIT["Foot_US",0.3048006096012192]]

Drawing Info:

Renderer:
Unique Value Renderer:
Field 1: Type
Field 2: null
Field 3: null
Field Delimiter: ,
Default Symbol:
N/A
Default Label: null
UniqueValueInfos:
• Value: Shallow Groundwater Likely 0-3 ft
  Label: Groundwater Likely 0-3 ft
  Description:
  Symbol:
  Style: esriSFSSolid
  Color: [215, 158, 158, 255]
  Outline:
  Style: esriSLSSolid
  Color: [0, 0, 0, 0]
  Width: 0
• Value: Shallow Groundwater Likely 3-6 ft
  Label: Groundwater Likely 3-6 ft
  Description:
  Symbol:
  Style: esriSFSSolid
  Color: [255, 255, 115, 255]
  Outline:
  Style: esriSLSSolid
  Color: [0, 0, 0, 0]
  Width: 0
• Value: Shallow Groundwater Likely 6-10 ft
  Label: Groundwater Likely 6-10 ft
  Description:
  Symbol:
  Style: esriSFSSolid
  Color: [163, 255, 115, 255]
  Outline:
  Style: esriSLSSolid
  Color: [0, 0, 0, 0]
  Width: 0
• Value: Potential Shallow Groundwater
  Label: Potential Shallow Groundwater
  Description:
  Symbol:
  Style: esriSFSSolid
  Color: [190, 210, 255, 255]
  Outline:
  Style: esriSLSSolid
  Color: [0, 0, 0, 0]
  Width: 0
Transparency: 0
Labeling Info:
Label Placement: esriServerPolygonPlacementAlwaysHorizontal
Label Expression: [Type]
Use Coded Values: true
Symbol:
Color: [0, 0, 0, 255]
Background Color: N/A
Outline Color: N/A
Vertical Alignment: bottom
Horizontal Alignment: center
Right to Left: false
Angle: 0
XOffset: 0
YOffset: 0
Size: 8
Font Family: Arial
Font Style: normal
Font Weight: normal
Font Decoration: none

Min. Scale: 4800.0
Max. Scale: 0.0

Advanced Query Capabilities:

Supports Statistics: true
Supports OrderBy: true
Supports Distinct: true
Supports Pagination: true
Supports TrueCurve: true
Supports Returning Query Extent: true
Supports Query With Distance: true
Supports Sql Expression: true
Supports Query With ResultType: false
Supports Returning Geometry Centroid: false
Supports Binning LOD: false
Supports Query With LOD Spatial Reference: false

HasZ: false

HasM: false

Has Attachments: false

HTML Popup Type: esriServerHTMLPopupTypeAsHTMLText

Type ID Field: null

Fields:

• OBJECTID ( type: esriFieldTypeOID, alias: OBJECTID )
• Type ( type: esriFieldTypeString, alias: Type, length: 50 )
• Code ( type: esriFieldTypeString, alias: Code, length: 50 )
• SHAPE ( type: esriFieldTypeGeometry, alias: Shape )
• SHAPE.STArea() ( type: esriFieldTypeDouble, alias: SHAPE.STArea() )
• SHAPE.STLength() ( type: esriFieldTypeDouble, alias: Shape.STLength() )

Supported Operations:   Query   Query Attachments   Generate Renderer   Return Updates

  Iteminfo   Thumbnail   Metadata